gspell and LaTeXila – progress report

In September I’ve launched two small fundraisings on gspell and LaTeXila. The two goals are now reached, thanks!

I’ve started working on those two projects, here is a progress report.

gspell – adding GtkEntry support

The basic infrastructure is there, and red wavy underlines are inserted to highlight misspelled words. The code is written in a way that it is unit-testable, and unit tests have been written.

Statistics so far:

21 files changed, 1921 insertions(+), 14 deletions(-)

Next steps:

  • The context menu (right-click menu).
  • Do not check the word currently typed.
  • Better word boundaries, to take into account apostrophes and dashes.

For all those next steps, the idea is to have common code between the GtkTextView and GtkEntry support.

LaTeXila – port to GAction/GMenu?

This progress report is a bit more technical.

To create the menu and toolbars, LaTeXila still uses the deprecated GtkUIManager and GtkAction. What I’ve done this week is investigation work, to figure out if it is possible to use GMenu (the new way menus are now usually created). GAction is great and will be used, but for GMenu it is more complicated.

The conclusion is that it will not be possible to use GMenu in LaTeXila. Because in LaTeXila, when hovering a menu item, a longer description is displayed in the status-bar – which makes the user interface self-discoverable – and this is not possible with GMenu (see this comment in bugzilla for more details). Thankfully GTK+ has a more basic way to create menus, with GtkMenuBar, GtkMenuItem etc. So that’s what LaTeXila will use.

Another reason to create a GtkMenuBar manually is to be able to add a sub-menu with the list of recently used files, with GtkRecentChooserMenu. This doesn’t exist as a GMenu, it would need to be implemented.

Also, the nice thing about GtkUIManager is that the information was encoded just once for both the menus and the toolbars. For a certain menu or toolbar item, the needed information is: the short description, the long description, the icon, the keyboard shortcut and the function to call when the action is activated. With GMenu, some of the information needs to be duplicated for creating a toolbar. So that’s another reason why not using GMenu (at least not directly).

So what I will do is to create a simplified GtkUIManager based on GAction. In other words, store the information just once, and have a convenient way to create menus and toolbars. To create a menu or toolbar item, all of what will be needed is to provide the action name; it will fetch the required missing information from a central store.

Posted in gspell, LaTeXila | 6 Comments

gspell and LaTeXila fundraisings – thanks!

The gspell fundraising has reached its initial goal! So thanks a lot for your support!

Expect GtkEntry support in the next version of gspell, which is planned for March 2017.

I’ve added a second milestone for the gspell fundraising, because there are a lot of other possible things to do.

The LaTeXila fundraising is going well too, it is currently at 80%. So thanks to the people who donated so far!

If you write documents in LaTeX, and care about having a good LaTeX editor, well maintained and well integrated to GNOME, then consider donating to LaTeXila ;) There will hopefully be other milestones in the future, for example to improve the auto-completion (e.g. complete the label in \ref commands), or implementing a full-screen mode.

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Two Small Fundraisings – on gspell and LaTeXila

We live in a world where it’s increasingly possible to have a part-time job and being paid for other small tasks on the side; think about Uber or airbnb.

I have a half-time job, and I care about Free Software. So the natural thing to do for me is to find ways to be funded for the contributions I do.

That’s why I was really pleased to hear Alexander Larsson, at the end of his talk at GUADEC about Flatpak:


[…]
And also an interesting thing – I think actually super important – is payment. I want people to be able to pay for Free Software.

Which was met with applause. But unfortunately such support in Flatpak and GNOME Software are not going to happen anytime soon, maybe in a few years with some hope.

In the meantime, I’m launching two small fundraisings!

If this is successful, the idea is to add further milestones, after the work is done on the first one.

gspell

gspell is a library that I created last year to share the spell-checking code between gedit and LaTeXila. The code comes from the gedit spell plugin, as such there is only the support for GtkTextView. The goal of the fundraiser is to add support for GtkEntry, a single line text entry field.

Go to the gspell fundraising page if you’re interested!

LaTeXila

GTK+ 3.22, which will be released this Wednesday, will be the last GTK+ 3 stable version (see this announcement). After that, the deprecated functionality of GTK+ 3 will be removed. LaTeXila is not a new application, it is developed since 2009. A fundraising on a new piece of software can concentrate on features. For LaTeXila, what is more important is that it is well maintained, to be still relevant in the 2020’s. So the fundraiser is to make the code ready for GTK+ 4, at least as a next step.

Code maintenance is not really what we can call interesting, but it is useful. We can see this interesting/useful dichotomy quite often in the computer science world: for a researcher, is proof of correctness interesting? Yes. But in practice it is rarely applied. Is writing unit tests interesting? No, but it is very useful.

Go to the LaTeXila fundraising page if you’re convinced ;)

Posted in gspell, LaTeXila | 8 Comments

Announcing Gtef, an incubator for GtkSourceView

Gtef – the acronym for “GNOME Text Editor Framework” – is a new library that eases the development of GtkSourceView-based text editors and IDEs. It can serve as an incubator for some GtkSourceView features.

See the Gtef repo on GitHub for more details. In particular, Gtef has an interesting way to handle API (un)stability. The Gtef Roadmap is alongside the GtkSourceView one.

Posted in Gtef, GtkSourceView | 2 Comments

Using the GtkSourceView API to write scripts that manipulate text

In the gnome-c-utils repository, I wrote some scripts that use the GtkSourceView library.

When a script needs to read some text, search something in it, and possibly edit the content, then having a GtkTextBuffer is really convenient.

GtkTextBuffer is good at navigating through text, with all the GtkTextIter functions. The content can be edited easily. And the GtkSourceView library adds interesting features like regex search & replace and file loading and saving with character encoding handling (GtkTextBuffer accepts only valid UTF-8).

So, that’s it. I just wanted to share that I find it convenient to write scripts with GtkSourceView (but maybe because I speak the GtkTextView/GtkSourceView API fluently).

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Semi-Object-Oriented Programming in C

Although I said last year that I’m not the right person to write a book about developing GLib/GTK+ applications and libraries, I continue slowly but surely.

There is now a new section called “Semi-Object-Oriented Programming in C”. This serves as a nice warming up for GObject.

Download the PDF:

The GLib/GTK+ Development Platform (version 0.5)

See also the NEWS file to know what changed since my last blog post on the subject.

Any comments or patches are welcome (the Git repo is here).

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Thoughts on the Linux Mint X-Apps forks

You may be aware that Linux Mint has forked several GNOME applications, either directly from GNOME (Totem -> Xplayer, Evince -> Xreader, Eye of GNOME -> Xviewer), or indirectly via MATE (gedit -> pluma -> XEd).

GNOME is like the Debian of the Linux desktops. But is it a good thing? In the current state of the code, I don’t think so and I’ll explain why, with a solution: creating more shared libraries.

At the end of the day, it’s just a matter of design and usability concerns. We can safely say that the main reason behind the forks is that the Linux Mint developers don’t like the new design of GNOME applications with a GtkHeaderBar.

And there are perfectly valid reasons to not like headerbars. For gedit for example, see the list of usability regressions at this wiki page.

Currently the trend is GtkHeaderBar, but what will it be in 5 years, 10 years? Let’s face it, GNOME is here just following the new trend that came with smartphones and tablets.

So, a GNOME application developer needs to know that:

  • A GUI is an ever-changing thing, exactly like the clothes that you bought last year are already obsolete, right?
  • When the GUI changes too much, other developers don’t like it and fork the project. For valid reasons or not, this doesn’t matter.

The four X-Apps forks account for roughly 200k lines of code. In the short-term it works, Linux Mint has apps with a traditional UI. But hey, porting the code to GTK+ 4 will be another beast, because the four X-Apps still use the deprecated GtkUIManager and GtkAction APIs, among other things.

But when we look at the codebase, there are a lot of code that could be shared between a GNOME app and its fork(s). So there is a solution: creating more shared libraries. The shared libraries would contain the backend code, of course, but also some basic blocks for the UI. The application would just need to glue things up together, assembling objects, binding GObject properties to GSettings, create the main GtkWindow and a few other things.

The difference would be that instead of forking 200k lines of code, it would be forking maybe 20k lines, which is more manageable to maintain in the long term.

In the case of gedit, making its code more re-usable is exactly what I do since several years, but for another reason: being able to create easily specialized text editors or small IDEs.

Beside avoiding code duplication, creating a shared library has the nice side effect that it is much better documented (usually), and with an API browser like Devhelp, it’s a breeze to discover and understand a new codebase, it permits to have a nice overview of the classes. It’s of course possible to have such documentation for application code, but in practice few developers do that, although it would be a big step towards lowering the barrier to entry for newcomers.

When untangling some code from an application and putting it in a shared library, it is also easier to make the code unit testable (and unit tested!), or at least write a mini interactive test in case of frontend code. Making the code more stable, getting closer to bug-free code and thus more successful software.

Developing a shared library doesn’t necessarily mean to provide backward compatibility during 10 years. Nothing prevents you from bumping the major version of the library every 6 months if needed, making the new version parallel-installable with the previous major versions. So that applications are not forced to update the code when there is an API break.

But creating a library is more difficult, API design is hard. But in my opinion it is worth it. GNOME is not only a desktop environment with an application suite, it is also a development platform.

Posted in gedit, gspell, GtkSourceView, Programming, Thoughts | 12 Comments

Doing things that scale

In the software world, and with internet, we can do a lot of things that scale.

Answering a user question on IRC doesn’t scale, only one person and a few lurkers will benefit from it. Answering a user question on a mailing list scales a little better, since the answer is archived and can be searched for. What really scales is instead to improve the reference manual. Yes, you know, documentation. That way, normally the question will not surface again. You have written the documentation once and N readers benefit from it, regardless of N. It scales!

Another example. Writing an application versus writing a library. Writing an application or end-user software already scales in the sense that the programmer writes the code once, but it can be copied and installed N times for almost the same cost as one time. Writing a library scales more, since it can benefit N programs, and thus N^2 users if we use the asymptotic notation. It’s no longer linear, it’s quadratic! The lower-level the library, the more it scales.

Providing your work under a free/libre license scales more, since it can be re-distributed freely on the internet. There are some start-ups in the world that reinvent the wheel by writing proprietary software and provide technical support in their region only. By writing a free software instead, other start-ups can pop up in other regions of the world, and will start contributing to your codebase (if it’s a copyleft license, that is). For the human being advancement, free software is better since it more easily permits to not reinvent the wheel. Provided that it’s a high-quality software.

This can go on and on. You get the picture. But doing something that scales is generally more difficult. It takes more time in the short-term, but in the long-term everybody wins.

Posted in Programming, Thoughts | Comments Off on Doing things that scale

API vs ABI

I repeatedly see other people doing the mistake, so a little reminder doesn’t hurt.

  • API: Application Programming Interface
  • ABI: Application Binary Interface

The difference can be easily explained by knowing what to do for some code when the API or ABI breaks in a library that the code depends on:

  • If only the ABI breaks, then you just need to re-compile the code.
  • If the API breaks, you need to adapt the code.
  • When the code doesn’t compile anymore, you need to adapt it, so it’s both an API and ABI break.
  • When the code still compiles fine but you need to adapt it, it’s only an API break.

Example of an ABI break only: when the size of a public struct changes.

Example of an ABI and API break: when a function is renamed.

Example of an API break only: CSS in GTK+ 3.20, or when a function doesn’t do the same as what was documented before (in an incompatible way).

That’s it.

Posted in Programming | 6 Comments

Libtool convenience library to unit test private functions

Only the public API of a library is exported, so when a program is dynamically linked to the DSO (Dynamic Shared Object), it can only use the public functions.

So how do you unit test the private classes of your library?

There is a simple solution, having a Libtool convenience library that contains the whole code of the library, but without an -export linker flag, so that all functions can still be accessed. You then link that *.la file to your unit tests and also to the real library where you add the appropriate -export flag.

You can see that in action in GtkSourceView and gspell. For example in gspell:

When you run make in verbose mode with make V=1, you see that the libtool commands statically link the convenience static library (a file with the *.a extension) into the unit test programs and into the DSO.

That way the *.c files are compiled only once, and adding a unit test to the testsuite/Makefile.am is straightforward.

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